import SwiftUI

struct FinishWalkSheet: View {
    let points: [GPSPoint]
    let durationSeconds: Int
    let distanceMeters: Double
    let onDiscard: () -> Void
    let onSaved: () -> Void

    @Environment(\.dismiss) private var dismiss

    @State private var name: String
    @State private var selectedDogIds: Set<Int> = []
    @State private var dogs: [Dog] = []
    @State private var isLoadingDogs = false
    @State private var isSaving = false
    @State private var errorMessage: String?

    init(
        points: [GPSPoint],
        durationSeconds: Int,
        distanceMeters: Double,
        onDiscard: @escaping () -> Void,
        onSaved: @escaping () -> Void
    ) {
        self.points = points
        self.durationSeconds = durationSeconds
        self.distanceMeters = distanceMeters
        self.onDiscard = onDiscard
        self.onSaved = onSaved

        let formatter = DateFormatter()
        formatter.locale = Locale(identifier: "de_DE")
        formatter.dateStyle = .medium
        _name = State(initialValue: "Gassi am \(formatter.string(from: .now))")
    }

    var body: some View {
        NavigationStack {
            Form {
                Section("Stats") {
                    LabeledContent("Distanz", value: String(format: "%.2f km", distanceMeters / 1000))
                    LabeledContent("Dauer", value: durationLabel)
                    LabeledContent("Punkte", value: "\(points.count)")
                }

                Section("Name") {
                    TextField("Name der Tour", text: $name)
                }

                Section("Hunde") {
                    if isLoadingDogs && dogs.isEmpty {
                        HStack { ProgressView(); Text("Lade Hunde…") }
                    } else if dogs.isEmpty {
                        Text("Keine Hunde gefunden. Wird gespeichert ohne Hund-Zuordnung.")
                            .font(.footnote)
                            .foregroundStyle(.secondary)
                    } else {
                        ForEach(dogs) { dog in
                            dogRow(dog)
                        }
                    }
                }

                if let errorMessage {
                    Section {
                        Text(errorMessage)
                            .font(.footnote)
                            .foregroundStyle(.red)
                    }
                }
            }
            .navigationTitle("Tour speichern")
            .navigationBarTitleDisplayMode(.inline)
            .toolbar {
                ToolbarItem(placement: .cancellationAction) {
                    Button("Verwerfen", role: .destructive) {
                        onDiscard()
                        dismiss()
                    }
                }
                ToolbarItem(placement: .confirmationAction) {
                    if isSaving {
                        ProgressView()
                    } else {
                        Button("Speichern") {
                            Task { await save() }
                        }
                        .disabled(canSave == false)
                    }
                }
            }
            .task { await loadDogs() }
            .interactiveDismissDisabled(isSaving)
        }
    }

    private func dogRow(_ dog: Dog) -> some View {
        let selected = selectedDogIds.contains(dog.id)
        return HStack {
            Image(systemName: selected ? "checkmark.circle.fill" : "circle")
                .foregroundStyle(selected ? Color.accentColor : .secondary)
            VStack(alignment: .leading) {
                Text(dog.name)
                if let rasse = dog.rasse, !rasse.isEmpty {
                    Text(rasse).font(.caption).foregroundStyle(.secondary)
                }
            }
            Spacer()
        }
        .contentShape(Rectangle())
        .onTapGesture {
            if selected {
                selectedDogIds.remove(dog.id)
            } else {
                selectedDogIds.insert(dog.id)
            }
        }
    }

    private var durationLabel: String {
        let mins = durationSeconds / 60
        let secs = durationSeconds % 60
        if mins >= 60 {
            return "\(mins / 60) h \(mins % 60) min"
        }
        return "\(mins) min \(secs) s"
    }

    private var canSave: Bool {
        !name.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty
            && points.count >= 2
            && !isSaving
    }

    private func loadDogs() async {
        isLoadingDogs = true
        defer { isLoadingDogs = false }
        do {
            let fetched: [Dog] = try await APIClient.shared.get("/api/dogs")
            self.dogs = fetched
            // If there's exactly one dog, pre-select it — saves a tap.
            if fetched.count == 1 {
                selectedDogIds = [fetched[0].id]
            }
        } catch {
            // Fall back gracefully — user can still save without dogs.
            print("FinishWalkSheet loadDogs failed: \(error)")
        }
    }

    private func save() async {
        isSaving = true
        errorMessage = nil
        defer { isSaving = false }
        let body = RouteCreateBody(
            name: name.trimmingCharacters(in: .whitespacesAndNewlines),
            gpsTrack: points,
            distanzKm: distanceMeters / 1000,
            dauerMin: max(1, durationSeconds / 60),
            dogIds: Array(selectedDogIds),
            isPublic: false
        )
        do {
            let _: RouteDetail = try await APIClient.shared.post("/api/routes", body: body)
            onSaved()
            dismiss()
        } catch {
            errorMessage = error.localizedDescription
        }
    }
}